Particulate material delivery system and method

ABSTRACT

In order to deliver porous particulate material into a cavity via a thin tube without substantially crushing the porous particulate material, a two-step process and an apparatus for use therein are provided. The two-step process involves inserting a first rod into the thin tube to push the porous particulate material therein; removing the first rod from the tube; and (a) inserting a second rod into the thin tube, or (b) joining a second rod with the first rod, and inserting the joined first rod and second rod, to push the porous particulate material which remains in the thin tube. In (a), the first rod has a cross sectional area significantly smaller than that of the thin tube, and the second rod has a cross sectional area which is about equal to that of the thin tube. In (b), each of the first rod and the second rod has a cross sectional area about half of the thin tube.

FIELD OF THE INVENTION

The present invention is related to a technique for deliveringparticulate material such as granules and pellets, in particular porousparticulate material, into a bone cavity, for enhancing bone ingrowth.Alternatively, liquid such as blood might be added to the particulatematerial prior to the delivery.

BACKGROUND OF THE INVENTION

The conventional syringe is designed for delivering liquid, or sometimespaste.

When the conventional syringe is used to deliver granules, in particularfragile porous granules, into a bone cavity, for enhancing boneingrowth, the frictions created between the surfaces of the granulesthemselves and between the surfaces of the granules and the innersurface of a barrel of the syringe and a thin tube connecting the barrelto the bone cavity are often too large to successfully complete thedelivery, especially when the granules are porous granules which wouldbe crushed by the friction.

WO 2016/010836 A discloses a new measure to solve the aforesaid deliverypuzzle, wherein a particulate material delivery system is providedcomprising a plunger and a divided tube, the divided tube has two ormore partial shells which are suitable to be coupled to each other, sothat a longitudinal channel is formed in the divided tube, each of thepartial shells is able to move longitudinally in relation to the other,and the plunger is able to be inserted into the longitudinal channel.The two or more partial shells are coupled to each other, andparticulate material is filled in the longitudinal channel. Theparticulate material is held steady by the plunger while the two or morepartial shells of the divided tube are withdrawn one at a time, so thatthe particulate material originally in the divided tube is exposedgradually from a distal end thereof, and thus falls from the dividedtube. Indeed, the measure provided in WO 2016/010836 A is able todeliver the particulate material with a minimum possible friction beingcreated, and to successfully deliver porous particulate material withoutcrushing it. However, a more convenient measure is still possible toachieve the same goals.

SUMMARY OF THE INVENTION

The gist of the present invention is to provide a new measure to deliverparticulate material, in particular porous particulate material, such asporous granules and porous pellets formed by bone cement. The measureprovided in the present invention is able to deliver the particulatematerial with less friction being created, and to deliver more porousparticulate material with less porous particulate material beingcrushed.

An apparatus for delivering particulate material constructed accordingto the present invention comprises the features recited in claim 1 andits dependent claims.

A system for delivering particulate material constructed according tothe present invention comprises the features recited in claim 2 and itsdependent claims.

The present invention further provides a method of deliveringparticulate material into a space comprising features recited in claim 4and its dependent claims.

As desired, liquid such as blood might be added to the particulatematerial prior to the delivery.

Preferred embodiments of the present invention include (but not limitedto) those recited in the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a granule delivery system(hereinafter abbreviated as GDS) constructed according to a firstpreferred embodiment of the present invention.

FIG. 2 is a perspective views showing the GDS in FIG. 1 being assembled.

FIG. 3 shows illustrative cross sectional outer profiles of variousdesigns of a first rod and a second rod for use in the GDS of thepresent invention.

FIG. 4 shows illustrative cross sectional inner profiles of variousdesigns of tubes for use in the GDS of the present inventioncorresponding to the plungers (rods) shown in FIG. 3.

FIG. 5 shows a first rod having a circular cross section and a secondrod having an annular cross section for use in the GDS of the presentinvention.

FIG. 6 is an illustrative cross sectional view showing an outer profileof a first rod and an inner profile of a tube of a GDS constructedaccording to a second preferred embodiment of the present invention instep 1 of a delivery method of the present invention.

FIG. 7 is an illustrative cross sectional view showing an outer profileof a second rod and an inner profile of a tube of a GDS constructedaccording to a second preferred embodiment of the present invention instep 1 of the delivery method of the present invention.

FIG. 8 is a perspective view showing a granule delivery systemconstructed according to a third preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

A granule delivery system (hereinafter abbreviated as GDS) constructedaccording to a first preferred embodiment of the present invention isshown in FIG. 1 and FIG. 2, wherein the GDS comprises a tube 10 having amajor portion having a channel 11 of a uniform circular cross section, afirst rod 5, a second rod 6 and a perforated cap 3. The tube 10 has afunnel like proximal end to facilitate the filling of porous granules(not shown in FIGS. 1 and 2) into the channel 11 thereof. The perforatedcap 3 is used to hold the porous granules having been filled in thechannel 11 of the tube 10, and allows the porous granules to be wet byliquid (e.g. blood) through perforations formed on the perforated cap 3.The rod 5 and the rod 6 are identical to each other in this embodiment,each of which has a half circular cross section and a half circularflange at a proximal end thereof, so that they can be joined to form aplunger adapted to be inserted into the tube 10 from the funnel likeproximal end thereof by holding the joined half circular flanges. Thejoined plunger has a cross sectional area about 80-98% of that of thechannel 11 of the tube 10. In addition to the half circular crosssection and the circular cross section used in this embodiment, othershapes are also possible, which are all shown in FIG. 3 and FIG. 4. Atwo-step method for delivering the porous granules through the channel11 of the tube 10 is developed in the present invention, which includes(1) inserting the first rod 5 into the channel 11 from the funnel likeproximal end and till another end of the tube 10 to push the porousgranules which have been filled in said channel 11, causing a portion ofthe porous granules to exit from another end of the tube; (2) removingthe first rod 5 from the tube 10, joining the first rod 5 and the secondrod 6 to form a plunger, and inserting the plunger (the joined first rod5 and second rod 6) into the channel 11 from the funnel like proximalend of the tube 10 to push the porous granules which remain-in thechannel 11 of the tube 10, causing a further portion of the porousgranules to exit from the another end of the tube 10. The inserting inthe step (2) is stopped when a desired amount of the porous granulesexits from the another end of the tube 10, or is all the way till theanother end of the tube 10 to empty the tube. Whenever some “resistance”is felt during the step (2) inserting, one can easily go back to thestep (1) by pushing only one of the two half rods 5, 6 from there, clearthe resistance and then continue the step (2) inserting without pullingout the plunger (the joined first rod 5 and second rod 6). This“resistance clearing” procedure can be carried out repeatedly until allthe remaining porous granules are injected.

In addition to the combination of two half circular cross sections usedin the first preferred embodiment of the present invention, it is alsopossible to use a different combination. As shown in FIG. 5, a first rod50 has a circular cross section and a second rod 60 has an annular crosssection having a central hole matching the circular cross section of thefirst rod 50, so that the first rod 50 and the second rod 60 can bejoined to form a plunger having a circular cross section. The first rod50 and the second rod 60 shown in FIG. 5 can play the same roles as thefirst rod 5 and the second rod 6 shown in FIG. 1 in the aforesaidtwo-step method for delivering the porous granules, and the aforesaid“resistance clearing” procedure. Apparently, the step (2) of thedelivery method of the present application can be carried out by using acircular cross sectional plunger corresponding to the joined plungerformed by the first rod 5 (50) and the second rod 6 (60). Alternatively,the circular cross sectional plunger for replacing the joined plunger ofthe first rod 5 (50) and the second rod 6 (60) in the step (2) may havea cross sectional area which is smaller than that of the joined firstrod 5 (50) and second rod 6 (60).

It is not necessary that the ratio of the cross sectional areas of thefirst rod to the second rod is about 50%: 50% as shown in FIG. 3.Instead of 50%: 50%, the ratio can be, for examples, 20%: 80%, 30%: 70%,40%: 60%, 60%: 40%, 70%: 30%, or 80%: 20%. It might be also workable inthe delivery method of the present application, when the ratio of thecross sectional areas of the first rod to the second rod is 20%: 70%,30%: 60%, 40%: 50%, 50%: 40%, 60%: 30%, 70%: 20%, or the like.

A GDS constructed according to a second preferred embodiment of thepresent invention is similar to the first preferred embodiment of thepresent invention except the first rod 5 and the second rod 6 shown inFIG. 1 and FIG. 2. In the second preferred embodiment, as shown in FIG.6 to FIG. 7, a first rod 500 has a circular cross section having a crosssectional area about 30-60% of that of the channel 11 of the tube 10,and a second rod 600 has a circular cross section having a crosssectional area about 80-98% of that of the channel 11 of the tube 10.The delivery method of the present invention is carried out by using thefirst rod 500 in the above-mentioned step (1) and using the second rod600 in the above-mentioned step (2).

A GDS constructed according to a third preferred embodiment of thepresent invention is similar to the first preferred embodiment of thepresent invention shown in FIG. 1 and FIG. 2; however, the distal end ofthe GDS is curved so that it is adapted to reach a site which cannot beor is difficult to be reached linearly. In the third preferredembodiment, as shown in FIG. 8, the GDS has a tube 10′ having a curvedsection 12 at a distal end thereof; a first rod 5′ having a halfcircular cross section 51 having a cross sectional area about 50% ofthat of a channel 11 of the tube 10′, and a thinner section 52 having areduced cross-sectional area in comparison with that of the section 51;and a second rod 6′ identical to the first rod 5′. The thinner section52 has a strength enough to allow the first rod 5′ to push the porousgranules filled in the channel 11 of the tube 10′, and a flexibility toallow a distal end of the first rod 5′ to enter the curved section 12 ofthe tube 10′. The delivery method of the present invention is carriedout by using the first rod 5′ in the above-mentioned step (1) and usinga joined plunger formed by the first rod 5′ and the second rod 6′ in theabove-mentioned step (2).

Apparently, the step (2) of the delivery method of the presentapplication can be carried out by using a single plunger having astructure corresponding to the joined plunger formed by the first rod 5′and the rod 6′.

Example 1: Plastic Tubes and Plungers Made by Rapid Prototyping (RP)

In this example the tubes and the plungers were made of plastic materialby rapid prototyping (RP).

Comparative One-Step Method

Porous granules having sizes between 0.8 to 0.42 mm filled in a thintube having a length and an inner diameter as shown in Table 1. Theweights of the filled tube and the empty tube were measured, so that theweight of the porous granules filled in the tube could be calculated(W0). The porous granules were then wet with water, and were pushed by acircular plunger having a length longer that of the tube and a diametermatches the inner diameter of the tube. The wet granules exited from thetube were dried by baking, gently broken into granules, and screened toobtain granules having a size less than 0.42 mm, which was weighed (W1).The percentage of (W0-W1)/W0 was calculated and listed in Table 1 as thegranule delivery yield.

Two-Step Method

Porous granules having sizes between 0.8 to 0.42 mm filled in a thintube having a length and an inner diameter as shown in Table 1. Theweights of the filled tube and the empty tube were measured, so that theweight of the porous granules filled in the tube could be calculated(W0). The porous granules were then wet with water, and were pushed by afirst rod, and a second rod after removing the first rod from the tube.The shapes of the cross sections of the first rod and the second rod areboth circular; however, the cross sectional area of the first rod issmaller than that of the second rod which has a diameter matching theinner diameter of the tube, as listed in Table 1. The wet granulesexited from the tube were dried by baking, gently broken into granules,and screened to obtain granules having a size less than 0.42 mm, whichwas weighed (W1). The percentage of (W0-W1)/W0 was calculated and listedin Table 1 as the granule delivery yield.

TABLE 1 1^(st) 2^(nd) plunger plunger Tube cross-section cross-sectionGranule Tube inner area (mm²) area (mm²) delivery Delivery length dia.(1^(st) step (2^(nd) step yield method (mm) (mm) insertion) insertion)(%) One step 180 5.0 19.6 — 39 (conventional one plastic plunger Onestep 180 4.0 12.6 — 32 (conventional one plastic plunger) One step 1803.0 7.1 — 0 (conventional one plastic plunger) One step 180 2.5 4.9 — 0(conventional one plastic plunger) Two-step (two 180 3.0 4.9 7.1 10round plastic plungers) Two-step (two 180 3.0 3.1 7.1 12 round plasticplungers) Two-step (two 180 3.0 0.8 7.1 15 round plastic plungers)Two-step (two 180 2.5 3.1 4.9 23 round plastic plungers)

The results shown in Table 1 indicate that the conventional one-stepmethod is difficult or impossible to deliver the porous granules throughtubes having a length of 180 mm and an inner diameter of 5 mm or less.By using the two-step method of the present invention with the firstthinner plunger and the second matching plunger, it becomes possible todeliver the porous granules through tubes having a length of 180 mm andan inner diameter of 3 mm or 2.5 mm.

Example 2: 316 Stainless Steel Tubes and Plungers

In this example the tubes and the plungers were made of 316 stainlesssteel.

Porous granules having sizes between 0.8 to 0.42 mm filled in a thintube having a length and an inner diameter as shown in Table 2. Theweights of the filled tube and the empty tube were measured, so that theweight of the porous granules filled in the tube could be calculated(W0). The porous granules were then wet with water, and were pushed by afirst rod (1^(st) plunger). A second rod identical to the first rod wasjoined with the first rod after removing the first rod from the tube,and then the joined first rod and second rod (2^(nd) plunger) wasinserted into the tube to push the porous granules remaining in thetube. The wet granules exited from the tube were dried by baking, gentlybroken into granules, and screened to obtain granules having a size lessthan 0.42 mm, which was weighed (W1). The percentage of (W0-W1)/W0 wascalculated and listed in Table 2 as the granule delivery yield.

TABLE 2 1^(st) plunger/ 1^(st) 2^(nd) plunger plunger combination Tubecross-section 2^(nd) cross-section Granule Tube inner area (mm²) plungerarea (mm²) delivery length dia. (1^(st) step cross-section (2^(nd) stepyield Delivery method (mm) (mm) insertion) area (mm²) insertion) (%)One-step (conventional one 200 3.0 7.1 — — 0 circular steel plunger)One-step (conventional one 200 4.0 12.6 — — 31.1 circular steel plunger)One-step (conventional one 200 5.0 19.6 — — 39.6 circular steel plunger)Two-step (two semi-circular 200 3.0 3.55  3.55  7.1 63.4 steel plungers)Two-step (two semi-circular 200 4.0 6.3 6.3 12.6 65.7 steel plungers)Two-step (two semi-circular 200 5.0 9.8 9.8 19.6 95.3 steel plungers)

The results shown in Table 1 and Table 2 indicate that the 316 stainlesssteel can provide a better delivery yield in comparison with the RPplastic material as evidenced by the runs using tubes having an innerdiameter of 3 mm. The results in Table 2 also show that the deliveryyield is satisfactory by using the two-step method of the presentinvention with the two semi-circular rods to deliver the porous granulesthrough tubes having a length of 200 mm and an inner diameter of 3.0 mm,and is as high as 95.3% when the inner diameter is 5.0 mm.

1. An apparatus for delivering particulate material comprising a tubethrough which the particulate material is delivered, which comprises amajor section having a channel of a uniform cross section; a first rodhaving a cross sectional area which is 10-90% of that of said channel;and a second rod having a cross sectional area which is less than orequal to that of said channel, so that each of the first rod and thesecond rod is adapted to be inserted into said channel from one end ofsaid tube.
 2. A system for delivering particulate material comprisingsaid particulate material; a tube through which the particulate materialis delivered, which comprises a major section having a channel of auniform cross section; and a first rod having a cross sectional areawhich is 10-90%, preferably 20-50%, of that of said channel, so that thefirst rod can be inserted into said channel from one end of said tube topush said particulate material filled in said channel in advance,causing a portion of said particulate material exit from another end ofsaid tube.
 3. The system of claim 2 further comprising a second rodhaving a cross sectional area which is less than or equal to that ofsaid channel, so that the second rod can be inserted into said channelfrom said one end of said tube after the first rod being removed fromsaid tube, causing a further portion of said particulate material exitfrom said another end of said tube.
 4. A method for deliveringparticulate material through a tube comprising a major section having achannel of a uniform cross section, said method comprising filling theparticulate material in said tube; inserting a first rod into saidchannel from one end of said tube to push said particulate materialfilled in said channel, causing a portion of said particulate materialexit from another end of said tube, wherein said first rod has a crosssectional area which is 10-90% of that of said channel.
 5. The method ofclaim 4 further comprising removing said first rod from said tube; andinserting a second rod into said channel from said one end of said tubeto push said particulate material which remains in said channel, causinga further portion of said particulate material exit from said anotherend of said tube, wherein said second rod has a cross sectional areawhich is less than or equal to that of said channel.
 6. The apparatus ofclaim 1, wherein each of the first rod and the second rod has a crosssectional area of 30-70% of a cross sectional area of said channel, anda combined cross sectional area of the first rod and the second rod isless than or equal to the cross sectional area of said channel;preferably, each of the first rod and the second rod has a crosssectional area of about 50% of the cross sectional area of said channel,and the combined cross sectional area of the first rod and the secondrod is about equal to the cross sectional area of said channel; morepreferably each of the first rod and the second rod has a half circularcross section.
 7. The apparatus of claim 1, wherein each of the firstrod and the second rod has a circular cross section, the cross sectionalarea of said first rod is 20-50% of that of said channel, and the crosssectional area of said second rod is 80-100% of that of said channel. 8.The system of claim 3, wherein each of the first rod and the second rodhas a circular cross section, the cross sectional area of said first rodis 20-50% of that of said channel, and the cross sectional area of saidsecond rod is 80-100% of that of said channel.
 9. The system of claim 3,wherein each of the first rod and the second rod has a cross sectionalarea of 30-70% of a cross sectional area of said channel, and a combinedcross sectional area of the first rod and the second rod is less than orequal to the cross sectional area of said channel, so that the first rodand the second rod can be joined and joinedly inserted into said channelfrom said one end of said tube after the first rod being removed fromsaid tube, causing the further portion of said particulate material exitfrom said another end of said tube; preferably, each of the first rodand the second rod has a cross sectional area of about 50% of the crosssectional area of said channel, and the combined cross sectional area ofthe first rod and the second rod is about equal to the cross sectionalarea of said channel; more preferably, each of the first rod and thesecond rod has a half circular cross section.
 10. The system of claim 3,wherein said particulate material is porous particulate material. 11.The method of claim 4, wherein the first rod having a cross sectionalarea which is 20-50% of the cross sectional area of said channel, andsaid method further comprises withdrawing said first rod from said tube;and inserting said first rod into said channel again to push saidparticulate material remains in said channel, causing a further portionof said particulate material exit from said another end of said tube;and optionally repeating said withdrawing and said inserting to causemore said particulate material exit from said another end of said tube.12. The method of claim 5, wherein each of the first rod and the secondrod has a circular cross section, the cross sectional area of said firstrod is 20-50% of that of said channel, and the cross sectional area ofsaid second rod is 80-100% of that of said channel.
 13. The method ofclaim 5, wherein each of the first rod and the second rod has a crosssectional area of 30-70% of a cross sectional area of said channel, anda combined cross sectional area of the first rod and the second rod isless than or equal to the cross sectional area of said channel, whereinthe first rod is joined to the second rod after the first rod beingremoved from said tube, and the second rod with the first rod joinedthereto is inserted into said channel from said one end of said tube;preferably, each of the first rod and the second rod has a crosssectional area of about 50% of the cross sectional area of said channel,and the combined cross sectional area of the first rod and the secondrod is about equal to the cross sectional area of said channel.
 14. Themethod of claim 4, wherein said particulate material is porousparticulate material.
 15. The apparatus of claim 1, wherein said majorsection of said tube is linear with a curved section at another end ofsaid tube, said first rod is linear having a uniform cross section witha thinner section between a distal end and a proximal end of said firstrod, wherein the uniform cross section has said cross sectional area ofsaid first rod, and said thinner section has a smaller cross sectionalarea compared to the uniform cross section, so that a distal end of thefirst rod is adapted to be inserted into the curved section at saidanother end of said tube when said first rod is inserted into saidchannel from said one end of said tube; wherein said second rod islinear having a uniform cross section with a thinner section between adistal end and a proximal end of said second rod, wherein the uniformcross section of said second rod has said cross sectional area of saidsecond rod, and said thinner section of said second rod has a smallercross sectional area compared to the uniform cross section of saidsecond rod, so that a distal end of the second rod is adapted to beinserted into the curved section at said another end of said tube whensaid second rod is inserted into said channel from said one end of saidtube.